For a UK return the tool has to do three things HMRC-specifically: pool each token under Section 104, apply the same-day and 30-day rules before the pool, and give you figures you can copy into the SA108 boxes. Every tool below claims all three. Where they differ is what happens when your data is imperfect, which for anyone with more than one exchange, it is. So this ranking is by failure mode, taken from the last twelve months of 1 and 2 star reviews, rather than by feature grid.
The short answer: Moonscape or Recap if you want HMRC-first tooling and a person to talk to; Koinly if you need the widest integration list and can live with email support in January; Crypto Tax Calculator if your complexity is DeFi; CoinTracker or CoinLedger only if you also file in the US, because both are built around the 8949 first.
We make Moonscape, so the top entry is a claim you should verify with a free import rather than take on trust. The competitor notes are drawn from public Trustpilot reviews, linked so you can read them in full.
What a UK return needs
- Section 104 pooling. Each token is one pool with an average cost. A tool that runs FIFO by default and calls it UK-ready will give you the wrong gain.
- Same-day then 30-day matching. Sell and rebuy within 30 days and HMRC matches the sale to the later purchase, not the pool. Get the order wrong and the gain is wrong.
- Transfers between your own wallets are not disposals. Unmatched transfers are the single largest source of phantom gains in every tool.
- SA108 figures. Number of disposals, proceeds, allowable costs, gains, losses, and a computation you could hand to HMRC if asked.
- Losses carried forward across tax years, which matters more than it used to now the annual exempt amount is £3,000.
The ranking
1. Moonscape
HMRC-first: S104 pooling with same-day and 30-day matching, SA108 figures with the computation behind every number, and losses carried forward across years. The design choice that matters for a UK return is the exceptions report: each asset carries a running balance, and a sale that dips below what you hold is flagged as a missing source, a must-fix item, rather than given a zero cost. The count of open items sits next to the total, so the SA108 figure comes with its own health check.
Pricing is one payment per tax year, £35 to £159 by real transaction count, and spam and dust airdrops never count toward it. Importing and reconciling are free. Support is a person within one business day, filing season included.
Watch for: the integration list is shorter than Koinly's. If you used an exchange we do not connect to, you are on CSV. If the exchange no longer exists, the Concierge rescue rebuilds the history by hand from £499 after a free diagnostic scan.
2. Recap
UK-only, with S104 pooling as the core of the product rather than a mode. The best pure-UK choice if your activity is exchange trading. Watch for: narrow coverage outside the UK, and less depth on DeFi positions.
3. Koinly
The widest integration list in the category and a proper UK report. It answered all 22 of its low-star reviews in the last year. Watch for: the reviews themselves. Wrong balances the user cannot trace, email-only support on a two to three day cycle in filing season, and imports that half-work for LP positions.
"My balances are all out and I doubt they're accurate." (Koinly, 1★, August 2026)
"I get one email every 2-3 days... and getting resolved answers around tax sensitive data can not wait." (Koinly, 1★, April 2026)
The Koinly alternatives, ranked by complaint goes deeper.
4. Crypto Tax Calculator
Known for DeFi classification, with a UK report. If your complexity is LPs, bridges and staking derivatives rather than exchange volume, start here or at Moonscape. Watch for: subscription pricing by transaction count.
5. CoinTracker
A strong US product with a UK mode. Watch for: pricing. The UK reviews specifically call out spam transactions counting toward a 250-transaction tier and a rise from £49 to £79 in under a year for the same plan.
"Limit is very low of only 250 transactions. Spam transactions are added meaning you have to pay the increased price." (CoinTracker, 1★, January 2026)
What people leave CoinTracker over has the rest.
6. CoinLedger
Cheap and simple for a US 8949; the UK report is secondary. Watch for: USDC booked at zero cost and Coinbase imports with missing fields in the 2026 reviews, both of which turn into inflated gains under S104 just as they do under FIFO.
How to test any of them in an hour
- Import your two biggest sources and one wallet you transferred between them.
- Find that transfer. If it shows as a disposal, stop; the tool has not matched it and your gain is wrong.
- Pick one token you sold and rebought within 30 days. Check the tool matched the sale to the rebuy, not the pool.
- Read the exceptions or "needs review" list before the total. A total with open exceptions is a guess.
Most of these tools let you import before paying. Import into Moonscape and run those four checks; no card, and the exceptions count tells you honestly whether the number is ready for the SA108. If you would rather see the output before importing anything, the sample UK reviewer pack is a full synthetic 2025/26 computation.